Brushing method and apparatus



March 20, 1962 R. o. PETERSON BRUSI-IING METHOD AND APPARATUS 3 Sheets-Sheet 1 Filed May 4, 1956 p m J a T N N m w E m m Q w. m m M Y m M mm .W R N 3% \\w A m NM. 1 5.. on N 8 mm 5 mm a m. 2 2 mm 8 w. 2 om v g O o 0 1 In w v m n w n w m N m o.

March 1962 R. o. PETERSON 3,026,219

BRUSHING METHOD AND APPARATUS Filed May 4, 1956 3 Sheets-Sheet 2 INVENTOR.

RUBf/V Q'PETERSON A TTORNEY March 20, 1962 R. o. PETERSON 3,025,219

BRUSHING METHOD AND APPARATUS Filed May 4, 1956 3 Sheets-Sheet 3 INVENTOR. RUBEN O. PETERSON owwrm Domzllg ATTORNEYS 3,026,219 BRUSHING METHOD AYD APPARATUS Ruben 0. Peterson, University Heights, Ohio, assignor to The Osborn Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Filed May 4, 1956, Ser. No. 582,806 28 Claims. (Cl. 134-9) This invention relates as indicated to a novel brushing method and apparatus, and more particularly to a method and means for surface conditioning and beneficiating metal strip, such operations including the removal of scale and other closely adherent coatings, small slivers and the like, the rounding of the sharp edges of small pits and scratches, reducing differences in hardness and associated physical qualities of small adjacent surface areas and small adjacent subsurface component formations, cleaning and polishing the surfaces, and reducing surface tension.

It has previously been appreciated that certain benefits may be obtained by brushing the convexly flexed surface of a continuously traveling work-piece such as steel strip, and reference may be had to Pecsok Patent No. 2,335,196 and Peterson Patent 2,666,282 for disclosures of particular devices for this purpose. As also taught in my co-pending application Serial No. 404,431, filed January 18, 1954, now Patent 2,757,486, certain important advantages may be obtained by brushing the concave surface of a flexed continuously traveling stripor like elongated work-piece. As pointed out in such application, this arrangement is particularly suited to the concurrent application of various types of abrasives and also the brush may be brought into engagement with the work throughout a very considerable arcuate portion of the periphery, greatly increasing the amount of work done at any particular rate of work-piece travel and brush rotation.

It is an object of the present invention to provide brushing apparatus adapted to brush both sides of a continuously traveling elongated work-piece such as steel strip and the like and to brush both sides where both convexly and concavely flexed, the brushes engaging the concavely flexed surfaces also serving as back-up rollers for the brushes engaging the convexly flexed surfaces.

Another object is to provide brushing apparatus and a method of brushing effective to operate upon the traveling work-piece at an angle to its path of travel, this of course also being at an angle to the direction in which the work-piece was previously processed as by rolling and the like. I have discovered that it is unexpectedly advantageous thus to brush the work-piece surface diagonally Where it is convexly and concavely flexed.

A further object is to provide such brushing apparatus so arranged that while the axes of the power driven rotary brushes are diagonally related to the path of travel of the work-piece and such work-piece is flexed first in one direction and then in the other direction, a straight line pass may nevertheless be achieved.

Still another object is to provide such method of brushing the work-piece wherein the direction of rotation of the brushes is periodically reversed and such brushes are also slowly reciprocated axially thereof transversely of the traveling work.

Other objects of the invention will appear as the description proceeds.

To the accomplishment of the foregoing and related ends, said invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but United States Patent "ice a few of the various ways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a diagrammatic side elevation of the introductory portion of a continuous strip treating line in accordance with my invention;

FIG. 2 is a continuation of the view of FIG. 1 showing the principal brush stands;

FIG. 3 is a similar view showing the terminal portion of the line;

FIG. 4 is a diagrammatic top plan view of the portion of the line shown in FIG. 2 indicating the manner in which the brushing stands may be swiveled at an angle to the path of travel of'the work; and

FIG. 5 is an elevational view of a double brush assembly adapted to engage opposite sides of a traveling steel strip, together with means for reciprocating such brushes tranversely of the work.

Referring now more particularly to said drawing and especially FIGS. l3 thereof, such figures illustrate a continuous strip beneficiating and conditioning line commencing with an uncoiler 1 from which the strip S passes along conveyor 2 to a stand journalling pinch rolls 3 and power driven strip feeding rolls 4. The next stand 5 journals a pair of power driven cylindrical duster brushes between which the traveling strip passes for removal of loose particles from its surfaces prior to passage through a roll stand 6 operative to flex and work the strip to fracture surface scale and regularize its cross-section. This roll stand will desirably be of the type disclosed and claimed in the application of John C. Bongiovanni Serial No. 513,641, filed June 7, 1955. The strip now passes through another duster brush stand 7 similar to stand 5 to clean the surfaces prior to passage of the strip through roll stand 8 similar to stand 6 but operative to flex the strip in the opposite direction as explained more in detail in such application of John C. Bongiovanni. After passing through a third duster brush stand 9, the strip is gripped by pinch rolls 10 and passes through a leveler 11 which assists in preparing the strip for operation thereon by the main brushing stands which follow. A brushing stand 12 precedes pinch rolls 13 and slitter 14 which may be utilized to slit the strip into desired widths prior to the performance of the principal brushing operations.

Referring now specifically to FIG. 2, strip S passes through successive brushing stands 15, 16, 17, 18, 19 and 20 which may desirably be of the type disclosed and claimed in my prior application Serial No. 491,992, Re ciprocating Surface-Finishing Mechanism and Method, filed March 3, 1955, or in application Serial No. 524,115 of John C. Bongiovanni, Brush Unit and Drive Means Therefor, filed July 25, 1955. These brush strands are mounted for reciprocation axially of the brushes journalled therein, and are also adapted to be swiveled so that such brush axes extend diagonally of the path of travel of the strip S, as discussed more in detail below. In view of such diagonal disposition in the brush axes and the fact that alternate stands are arranged in alternate higher and lower positions, there will be a tendency for the strip to angle first to one side and then to the other as it is flexed over brushes in such alternate stands. The strip would accordingly follow a slightly Zigzag path as viewed from above. This undesirable consequence is readily avoided by mounting such stands or the brushes thereof on a slight tilt to compensate therefor. In fact, with the adjustable arrangements provided for the pairs of opposed cylindrical rotary brushes, it is ordinarily feasible merely to adjust the bearing chocks slightly to incline the brush axes without thus inclining the entire brushing stand.

It will be seen that the strip S is first flexed about upper brush 21 in stand 15, with the lower brush 22 engaging the convexly curved under surface of the strip. Such strip is then flexed over lower brush 23 of stand 16, such lower brush serving as a back-up roll for upper brush 24 engaging the convexly flexedupper surface of the strip. Upper brushes 25 and 26 in stands lfiand 20 respectively correspond to such brush 24 in stand 16 with lower brushes 27 and 28 corresponding to brush 23. Intermediate the stands 16 and 18 the traveling strip is flexed about the cylindrical upper brush 29 of stand 17 with lower brush 30 engaging the convexly curved under surface. of the strip. In stand 19, similarly, the strip is flexed about upper brush 31 with lower brush 32 engaging the convexly curved under surface of the strip.

Referring now to FIG. 3, the strip continues from stand 20 through pinch roll stand 33 to conveyor 34, recoiler 35 and delivery conveyor 36. Ordinarily, the leading end of a following length of strip will be welded to the trailing end of a preceding length so that operation of the brushing line may be substantially continuous. A parting shear (not shown) will then be required ahead of coiler 35. Of course, other equipment such as a squaring shear, welder, coil opener and accumulator may also be included at the entry end of the line. Except for the accumulator hereinafter described, such equipment may be of standard design well known in the art.

As shown in FIG. 4, which is a diagrammatic top plan view of FIG. 2, the brushing stands 15, 16, 17, 18, 19 and 20 may be swiveled in either direction as desired in order that the axes of the cylindrical brushes of such stands may extend at least somewhat diagonally of the path of travel of the strip S rather than at right angles thereto.

Preliminary Treatment It has been general practice in the past to remove scale from steel strip and the like by passing such strip through a scale breaker and then through a long and wasteful pickling operation. Acid pickling methods are quite effective in removal of oxide scale, but they also involve the removal of some good metal (frequently more than one percent) unless so inhibited as greatly to slow the operation and do not assist in reducing slivers, burrs, and other surface irregularities. The pickling acids preferentially attack certain portions of the metal surface, thus producing and exaggerating numerous weakening and otherwise objectionable pits and sharp etchings, and hydrogen liberated as the acid does its work is absorbed into the steel or other metal to a considerable extent with some resultant embrittlement of the metal and other detrimental effects. Despite subsequent washing operations, minute amounts of the pickling solution and resultant salts and other water-borne materials, after drying, tend to remain in such small pits and surface irregularities where they may subsequently cause considerable trouble. Sulphuric acid is the acid most usually employed, and the supply is not always as stable as might be desired.

Of course, the pickling operation does not entirely use up the acids supplied to the pickling tank, and frequently more than half the acid and the salts must in due course be discarded or salvaged. Disposition of the partially spent solutions containing mixtures of acids and metal salts is both a troublesome and a costly problem. Increasingly severe pollution control laws are making such problem even more severe. Salvaging operations do not return their cost.

While the present invention relates primarily to a novel method and apparatus for brushing continuously traveling elongated metal articles such as steel strip, it will be appreciated from the preceding general description of the complete line that several preliminary operations are important to place the strip in best condition for effective action thereon by the main brush stands 15, 16, 17, 18, 19 and 20. More particularly, I very much prefer to employ a scale loosening and strip beneficiating apparatus of the type disclosed in the aforesaid Bongiovanni application Serial No. 513,641 (sta d? d 3 herein) instead of the well-known but much less effective con-- ventional scale breakers utilized in advance of the custom-- ary pickling tanks. This new apparatus may comprise a power driven back-up roll or rolls supporting a very much smaller diameter work roll thereagainst for free rotation and a pair of parallel larger work rolls slightly spaced from such smaller work roll and asymmetrically posi-' tioned of such back-up roll assembly, with power means operative to drive such larger work rolls. The strip passesover the smaller work roll between the same and two larger work rolls, being forced to flex about a radius preferably at least as small as that of such smaller work roll. This controlled flexing is very effective in fracturing and loosening the scale and in improving the physical qualities of the base metal, and the strip will desirably be flexed first in one direction and then in the other in such stands 6 and 8.

The roller leveler 11"'will preferably employ a large number of rollers in order that the traveling strip may be well leveled after the preceding flexing operations, a substantially flat surface (only very slightly wavy) being of advantage in the subsequent brushing operations. Although their inclusion in the line is optional, when included, the duster stands 5, 7 and 9 clean the strip surfaces of relatively loosely adherent dirt and scale but are not relied upon to remove tight scale. These stands may desirably be mounted for reciprocation transversely of the path of travel of the strip in the manner explained in my prior application Serial No. 491,992, the cylindrical brushes being of somewhat greater axial extent than the width of the strip engaged and the reciprocation being regulated to bring each end of the brush in to the adjacent edge of the strip and then out again alternately. The brush stands may, if desired, be arranged somewhat diagonally of the path of travel of the strip with their axes inclined at angles of from about 5 to 45 from a directly transverse position (i.e. from a position with their axes at right angles to such path of travel). Alternate brush stands may be thus inclined in opposite or different directions so as to brush the strip at different angles. The principal purpose of the duster brushes is to remove loose particles from the strip surface which might otherwise be pressed into and damage such surfaces when passing through the devices such as the scale fracturing stands 6 and 8, the leveler 11, and the pinch rolls. To avoid excessive duling of cutters of slitter 13, 14, brushing stand 12 is placed therebefore.

If the strip is to be slit, it is preferred to perform this operation at the point indicated in the line since a considerable amount of the scale and other material likely to harm or cause undue wear of the slitting mechanism will already have been eliminated at this point. Also, by slitting the strip prior to the performance of the principal brushing operations thereon, the slit edges of the several resulting strips may be efiectively brushed in a manner explained in some'detail in my prior application Serial No. 491,992. 9 l

The Principal Brushing Operation The principal power driven brush stands 1520 (FIG. 2) are generally comparable to those shown and described in my prior application Serial No. 491,992, preferably being arranged diagonally of the path of travel of the work and providing for axial reciprocation of the brushes. The principal difference in such FIG. 2 arrangement of the brushing stands resides in the fact that the pairs of brushes of alternate stands are. at different levels so that the strip is flexed first in one direction and then the other about one brush of each pair. Accordingly, one brush of each stand serves as a back upiroll supporting thestrip for the associated brush which may engage 'and brush the convexly flexed surface of the strip. Also, the back-up brush itself power brushes the concavely flexed surface engaged thereby. When the strip being brushed is less than a'certain minimum thickness (usually on the order of about one-sixteenth of an inch), however, it may generally be preferred that such associated brush engage the strip surface immediately in advance of or immediately following the arc of flexing where such strip surface is relatively flat.

My cylindrical rotary brushes make excellent supports over which to flex the traveling strip. It is well known that slivers and abrasive particles embed in and adhere to the surface of most solid rolls. The softer such rolls, the greater the tendency to hold such particles. Slippage, unavoidable in systems of the type in question, between the strip and the surface of -a supporting roll therefore is inclined to mar the surface, and especially after such a system has been in operation for some time. In contrast to this, such slivers and abrasive particles sink deep into the brush face on the support side, and fall out on the opposite side. The numerous points of brush bristles, even though they be made of the hardest of wire, do not scratch deeply. Such scratching as takes place in limited to a burnishing action which is beneficial rather than detrimental.

A further important feature in association with the foregoing is the arrangement or disposition of these brush stands diagonally of the path of travel of the strip S so that the direction of brushing is likewise diagonal and, moreover, diagonal to the direction in which the strip was previously processed when rolled. Small surface irregularities and slivers which were pressed into the surface of the strip during such rolling operation normally lie in directions parallel to the direction of strip travel (i.e. directly longitudinally of the strip) and are far more effectively engaged by the brush bristle material if the direction of brushing is at least partially laterally thereof and applied subsequent to processing by the scale breaking and beneficiating device described above.

This combined arrangement of alternately higher and lower pairs of brushes together with the diagonal disposition of such brushes introduces certain problems. In the first place, it is desirable that alternate pairs of brushes be thus diagonally disposed an equal amount in opposite directions in order that the strip may not be diverted laterally from a straight pass line although, of course, its path does not lie in the same horizontal plane throughout. To accomplish this end, it is further desirable slightly to tilt the stands or the brushes thereof tranversely of the path of travel of the strip by raising the rearward end of each stand or pair of brushes slightly. The slight zigzag path or irregularity of tension which would otherwise be produced is thus avoided.

Referring now more specifically to FIG. 4 of the drawing, I have found it advantageous ordinarily to dispose the endmost stands of a series, in this case stands 15 and 20, at relatively small angles to a position directly normal to the path of strip travel, such as approximately 5 for example. The intermediate stands may desirably be placed at somewhat larger angles such as from about to about 30 from such normal position, and the angle may be as much as 45. In addition to thus arranging the brush stands so that the directions of brushing are angularly related to the path of travel of the strip, it will be seen that such directions of brushing are also desirably angularly related to each other so that each point of the surface area of the work is brushed in several different directions, preferably at least three or four. This action can be facilitated and enhanced by rotating the brushes in similarly angularly disposed stands in opposite directions. The directions of rotation of these brushes should be periodically reversed as required to maintain uniform brushing action by preventing undue rounding and dulling of the wire brush material bristle ends. The brushes may also (or alternatively) be sharpened by periodically or continuously dressing the same.

While I have shown six brushing stands in FIG. 2, providing six power driven brushes engaging each side of the strip (three brushes on each side able to engage the convexly flexed surface and three brushes on each side engaging the concavely flexed surface), and also the power driven brush stand 12 operative to perform an effective brushing operation in advance of slitter 13, this ordinarily being adequate when the strip is traveling at a rate of from to feet per minute, I will ordinarily desire to employ about ten brush stands arranged as in FIG. 2 with such brushes engaging each side when the strip is to travel from about 250 to about 300 feet per minute. Of course, it will be appreciated that certain types of strip are more readily cleaned and descaled than others, and much will also depend upon the efliciency of the preceding scale fracturing method and apparatus which may be of the type above identified or of other types Well known in the art such as shot blasting, for example.

In a typical operation, hot rolled steel strip having a thickness of from .060 to .148 inch and a width of from 6 to 54 inches, or of greater width, may be threaded through the line at 20 feet per minute and thereafter substantially continuously processed at from 100 to 300 feet per minute. A typical coil may weigh about 750 pounds per inch of width. The scale removing brushes using wire brush material may be operated at speeds on the order of 10,000 surface feet per minute and their directions of rotation should periodically be reversed after about three minutes of brushing time, for example. When brushes substantially larger than the width of strip being brushed are used and reciprocated transversely of the strip as described above, then the time between reversals of brush rotation can be lengthened proportionately. The cutting and wearing qualities of the brush material of which the brush is made will, of course, also affect the length of the period between reversals. As taught in my aforesaid application Serial No. 491,992, the length of the brush face should desirably be substantially greater than the effective width of the work (as much as 25 to 100% greater) and the brush slowly oscillated transversely of the work to bring the respective ends of the brush alternately closely approaching the corresponding side edges of the work. This ensures that the usually more heavily scaled edge portions will be brushed by brush material which is not in engagement with the work at all times and therefore on the average less dulled prior to brush rever sal. Furthermore, the usual edge burrs are more eifec tively acted upon.

I have found that brushing the same surface both when it is concavely flexed and also when it is convexly flexed is unexpectedly effective in the removal of scale and slivers and more so than when brushing the same surface an equal number of times only where convexly flexed or where not flexed. It appears that the brushing of the convexly flexed surface, involving a relatively small area of contact, achieves a picking action effective by impact to lift off scale particles and slivers whereas the brushing of the concavely flexed surface, involving a relatively large area of contact, achieves a more intense surface brushing action while adhering scale particles and base metal adja cent thereto and surrounding the small slivers are subjected to compressive force which tends to pry outwardly the scale particles and small slivers and weaken their bond at the time of brushing. Each type of brushing action better prepares the surface for the other type of brushing action and the combination of such features, including the plurality of directions of brushing, results in complete removal of the fractured surface scale and most of the small slivers.

Suitable means for reciprocating the brushing stand transversely of the traveling strip is disclosed in my prior co-pending application Serial No. 491,992, filed March 3, 1955, for Reciprocating Surface-finishing Mechanism and Method, to which reference may be had for a detailed description of such mechanism. As shown in FIG. 5 of this application, however, a carriage 37 may be mounted upon a pair of parallel rails such as 38 by means of wheels such as 39, 40, 41 and 42. Both the brushing 1 unit and the power drive unit are supported on such carriage for adjustable positioning therealong. The power 'unit may comprise a double decked support carrying platforms 43 and 44 on which are mounted reversible motors 45 and 46 respectively. Motor 45 is operative to drive the lower of the two cylindrical brushes described below, and motor 46 is operative to drive the upper brush of such pair.

The brushing unit comprises a frame formed of two open rectangular end members 47 and 48 mounted on ways on the carriage and connected by a headpiece 49. Their lower ends are connected by tension rods and spacer sleeves 50 (shown partly broken away in FIG.

A pair of opposed roller brushes 51 and 52 are journalled within housings 53 and 54 respectively. Such brush and housing assemblies may desirably be of the general type shown and described more in detail in my prior Patent No. 2,800,677. The ends of housing 53 are supported by vertical screws threadedly engaging the same and adapted to be driven in unison through motor 55, worm gear reduction unit 5 6, shaft 57, and worm gear units 58 and 59. A clutch 60 is provided whereby unit 59 may be disengaged to permit individual drive for correction of axial canting of the brush.

The ends of upper housing 54 are similarly supported by vertical screws such as 61 threadedly engaging the same and adapted to be driven in unison through motor 62, worm gear reduction unit 63, shaft 64 and worm gear units 65 and 66. By means of such screw drive means, the housings and thereby the brushes may be moved toward and away from each other as may be required.

Means is provided for adjustably reciprocating carriage 37 back and forth on the track such as 38 comprising a hydraulic cylinder 67 mounted on a rigid base intermediate and parallel to the rails such as 38, and having a piston reciprocable therein, the rod 68 of which is connected to a cross-member of carriage 37. The cylinder is of the double-acting type whereby carriage 37 may be caused to reciprocate back and forth on the track with consequent reciprocation of the brushing stand and brushes 51 and 52.

The power driven brushes which engage the surfaces of the strip at or closely adjacent the regions where convexly flexed will ordinarily be moved out of effective brushing engagement with the strip whenever the line is momentarily stopped to provide for reversal of such brushes and the pressure of the strip against the brushes engaging the concavely flexed surfaces may likewise desirably be reduced to render such latter brushes ineffective when they are thus stopped and their directions of rotation are reversed. If heavy strip is being brushed, lifting rolls may be provided adjacent such brush stands temporarily to hold the strip away from the respective brushes. During this brief interval it will also usually be found advantageous to back up the strip (i.e. return 1 it several feet in the reverse direction) before again effectively engaging it under normal operating pressure with such power driven brushes, now rotating in the other direction, and simultaneously again accelerating the strip to normal speed in a forward direction. Reference may be had to the aforesaid Bongiovanni application Serial No. 524,115 for one type of such controlled brush reversing means. Although my new brushing line may thus be maintained in substantially continuous operation, it is nevertheless one of its advantages that it may be stopped when desired without damage to the work, whereas a proper rate of travel through the pickling tanks of course requires to be maintained to avoid overor under-pickling. 'Ihe brushed strip may also pass directly to other work stations for performance of other operations thereon, such as galvanizing, instead of passing directly to coiler 35.

It will be appreciated that for best results the metal strip where engaged by the brushes should be as free of waviness as practical to ensure uniform contact of the brushes with the entire strip surface. The preferred scale fracturing mechanism briefly described above assists in eliminating major irregularities and the leveler 11 further assists in affording a true surface. There will nevertheless ordinarily be certain slight waves, ripples and slight widthwise curvature in the strip which would result in somewhat uneven brushing if such strip were not flexed at or closely adjacent the region where actually engaged by the brush. Even relatively slight flexing transversely of the strip is quite effective to displace such waves or ripples and present a smooth local area for engagement with the brush. The tensioning of the strip over alternately higher and lower brushes as shown in FIG. 2 further assists in achieving this highly desirable result.

Instead of arranging the opposed brushes of each pair directly opposite each other as shown in FIG. 2, the brush axes may be slightly relatively oflset along the pass line so that the brush on the convex side of the strip engages the latter approximately at an end of its are of flexure, i.e. immediately before or immediatelyafter it is flexed about the supporting brush. Tensioning of the strip about such latter brush serves to ensure that the strip surface is flat in the region thus engaged by the opposed brush. This slightly modified arrangement is often desirable when relatively thin strip is to be processed and helps in avoiding generation of excessive heat and possible interference between the opposed brushes. Thus, when steel strip is only 1 inch thick, for example, the two regions of contact with the respective brushes of the pair may be separated by as much as eight times the distance they would be separated if the strip surface were engaged where convexly flexed. V

In general, the strip will be flexed as shown in FIG. 2 so as to deviate from a straight line by forming included angles on the concave side of from about 179 to about or even less.

It will be seen that I have provided a method and apparatus for processing metal strip and the like to modify the surface of the same and to remove small islands of scale and debris left after the scale breaking operation as well as to remove small slivers which have been displaced from their pressed-in positions in the surface of the strip during the scale breaking and regularizing operation. The brushing operations furthermore serve to eliminate the sharp corners representing irregular edges of small pits and other superficial blemishes including the depressions left in the surface from displacement of small slivers. Certain of these objectionable features which it is desired to remove are oriented in a manner affording only one best angle of attack, and it is accordingly important that the strip surface be power brushed in a variety of different angularly related directions to ensure effective action thereon. By my new strip processing method, I am enabled to produce a scale-free and superior metal surface without at the same time objectionably abrading such surface to remove any consequential amount of the base metal.

As indicated above, there are practical considerations such as the periods of deceleration and acceleration of the brushes prior and subsequent to reversal of direction of rotation of the same which render it desirable to move the strip a short distance in a backward direction during the, period such brushes are decelerated and after such brushes have been withdrawn from contact with the strip or their contact pressures at least efiectively reduced. The strip should not be stopped at any time when the brushes arein f ullpressure contact therewith and rotating at full speed since this would result in over-brushing a line transversely of the strip. Accordingly, the strip should continue to move in its forward direction until effective contact with all of the operating brushes has been substantially reduced. This, however, obviously creates a situation tending to afford under-brushed portions transversely of the strip and it is therefore desirable to move the strip a short distance in a rearward direction so that such underbrushed portions will again be power brushed. When the brushes are up to their operating speed in their new direc- 9 tions of rotation, the strip will start moving in its forward direction before the brushes re-contact it. The strip is accordingly already in movement at the time the brushes efiectively re-contact the same. By this arrangement, both over-brushing and under-brushing of local areas are avoided. Simple idler rolls may be provided to each side of the brushes engaging the concavely flexed strip surfaces to engage the strip when such brushes are retracted.

When it is desired to maintain generally uniform tension on a strip being processed, it will often be best to rotate the brushes of each pair in the same direction (so that they engage the strip in opposite directions) but it will normally be desirable when threading a new strip to rotate both brushes of each pair in the direction to pull in the leading end of the strip. Of course, this problem can largely be avoided by employment of a leader strip.

The cylindrical rotary brushes which I will normally employ for my purpose in the FIG. 2 brush stands will be on the order of 24 inches to 30 inches in diameter and will be well balanced for high speed operation. The brush bristle material will ordinarily be crimped tool steel wire which may additionally be provided with a coating of a plastic such as nylon. (See my prior Patent No. 2,682,734.) Such brush bristles or filaments will normally protrude from the brush back which retains them a distance of about 2 to 3 inches when the brushes are new. While the diameter of the brush filaments will vary depending upon the material being brushed, the wire used therein will ordinarily range from about .005 inch to .015 inch in diameter. A very dense fill is desired, this being somewhat controlled by the depth of the crimp in the wire and each individual filament or bristle will have freedom of movement to a limited extent. The crimp in the wire provides a certain amount of spring action radially of the brush when forces are exerted in that direction. Such forces may, for example, be the pressure of the work against the brush or centrifugal force applying an outward pull on the filaments. Accordingly, brushes of this type are adapted to withstand considerable working pressures and yet the component wire bristles tend to extend somewhat radially to ensure brushing contact even in local regions of relatively low pressure (e.g. slightly recessed regions in the surface of the work-piece).

I have found that the employment of cylindrical brushes as back-up rolls for the work where such work is engaged by power driven brushes operating on or closely adjacent the convexly flexed region of the strip surface is superior to employment of conventional cylindrical steel back-up rolls in several respects, particles of scale and the like not being pressed into the strip surface thereby and there being no tendency to develop deep gouges and markings in such surface as often occurs with conventional rolls. Of course, such brushes supporting the concavely flexed surfaces are also driven at high rates of speed relative to the rate of travel to the strip to perform a further and especially effective brushing operation thereon as explained above.

As shown in my Patent No. 2,680,938, for example, the rotary brushes themselves may be provided with an internal feed for fluids and abrasives which may thus be delivered to the work surface from the interior of the brush by the action of centrifugal force. When such means are employed, it will also ordinarily be desirable to provide suitable adjacent suction hoods to carry away the abrasive particles after they have served their purpose as well as the material removed from the work. Associated suction hoods may also ordinarily be provided for collecting the scale particles removed by the fracturing and brushing mechanisms when no such auxiliary fluid or abrasive is used, the scale particles being of value for several purposes, notably powder metallurgy. Many types of work may be brushed in accordance with my invention, including ferrous and non-ferrous strip, rod and wire. Side guides for laterally positioning the work and other conventional auxiliary devices have not been shown 10 or described since they comprise no part of the invention and are well understood by those skilled in the art.

In addition to the improved quality of steel strip processed in accordance with my invention, there is a flexibility to the brushing line which constitutes yet another advantage over the usual pickling operation. Thus, a hot rolling mill characterized as a 60-inch mill will roll strip to a maximum width of 56 inches and will ordinarily be operated to produce strip of an average width considerably less than this. Such a mill may ordinarily produce about 100,000 tons of strip averaging about 4 feet in width and 3 inch in thicknes in one months time. About 70% of such product may go to a subsequent pickling or other scale removing operation so that the pickling or scale removing facilities must be capable of handling about 70,000 tons of strip in any given month if it is associated with a 60-inch mill as described above. Ordinarily, however, a single pickling line of even the most advanced modern design cannot handle this much product in a onemonth period and accordingly two pickling lines are usually required to process the product of one 60-inch hot rolling mill. With my new brushing method, however, it becomes possible to arrange a single line capable of handling the product of such a mill although two smaller lines may, of course, be provided if preferred. The faster line will require an increased number of brushing stands for the obvious reason that strip moving rapidly through the line will not receive as much brushing at any one station as would strip moving less rapidly.

Likewise, the number of brushes to be utilized in my new accumulator will depend to a considerable extent on the rapidity with which the strip is processed through the line.

I have found that a considerable amount of good metal which is usually removed by pickling methods is saved when my new method is employed, this usually amounting to about 1% (plus or minus A%) of the weight of the strip processed. Obviously, in the case of the 60-inch hot rolling mill taken as an example, this would constitute a saving of approximately 700 tons of good steel per month. Of course, the disposal of spent pickling liquor is rapidly becoming a very serious and expensive problem, and a further consequential saving is thus achieved by elimination of the pickling process.

Other modes of applying the principle of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

I therefore particularly point out and distinctly claim as my invention:

1. Apparatus for brushing a length of metal strip or the like comprising a pair of opposed rotary wire brushes adapted to engage opposite sides of such strip passing therebetween, means operative positively to flex such strip concavely over one said brush, and means operative to drive the other said brush at a speed effective to power brush the convexly flexed surface of such strip.

2. Apparatus for brushing a length of metal strip or the like comprising a pair of opposed rotary dense wire brushes adapted to engage opposite sides of such strip passing therebetween, means operative to advance such strip, means operative positively to flex such strip concavely over one said brush to present a concave surface thereto while presenting a convex surface to the other said brush, and means operative to drive said brushes at effective brushing speeds much in excess of the speed at which such strip is thus advanced, thereby simultaneously brushing both said convexly flexed and said concavely flexed surfaces.

3. Apparatus for brushing a length of metal strip or v the like comprising at least three successive pairs of opposed rotary brushes adapted to engage opposite sides of such strip passing therebetween, the intermediate said pair of brushes being offset from said other two pairs to enforce a zigzag path of travel on such strip, means operative to tension such strip to flex it about one brush of each of said pairs and to advance such strip, and means operative to drive said brushes at eflective brushing speeds much in excess of the speed at which such strip is thus advanced, thereby simultaneously brushing both said convexly flexed and said concavely flexed surfaces.

4. Apparatus for brushing a length of metal strip or the like comprising a succession of pairs of opposed rotary brushes offset to flex such strip passing therebetween in a zigzag path, means operative to advance such strip, and means operative to drive said brushes to brush both the convexly flexed and the concavely flexed portions of such strip.

5. The apparatus of claim 4 wherein said pairs of brushes are disposed diagonally of the longitudinal center line of such strip.

6. The apparatus of claim 4 wherein said pairs of brushes are disposed diagonally of the longitudinal center line of such strip, alternate pairs being relatively angled successively to brush the same portion of such strip in substantially different directions.

7. The apparatus of claim 4 wherein the axes of said brushes are generally horizontal and disposed diagonally of the longitudinal center line of such strip, said axes being slightly tilted from the horizontal sufliciently to compensate for such diagonal arrangement to produce a straight pass as viewed in top plan.

8. The apparatus of claim 4 wherein the axes of said brushes are generally horizontal and disposed diagonally of the longitudinal center line of such strip, said axes being slightly tilted from the horizontal sufliciently to compensate for such diagonal arrangement to produce a straight pass as viewed in top plan, alternate pairs being relatively angled successively to brush the same portion of such strip in substantially different angularly related directions.

9. The apparatus of claim 4 wherein the axes of saidbiushes are generally horizontal and disposed diagonally of the longitudinal center line of such strip, said axes being slightly tilted from the horizontal sufliciently to compensate for such diagonal arrangement to produce a straight pass as viewed in topplan, alternate pairs being relatively angled successively to brush the same portion of such strip in substantially different angularly related directions, and including means operative slowly to reciprocate said brushes transversely of such strip.

10. In a line for processing elongated articles such as metal strip and the like, means operative to flex such strip in a zigzag path, power driven brushes arranged successively to brush both concavely flexed and convexly flexed portions of the same strip surface, and means operative to advance such strip along such path.

11. In apparatus for treating elongated articles such as metal strip and the like, means for longitudinally advancing such strip, means operative to flex suchadvancing strip diagonally of its longitudinal center line, and brush means operative to power brush the convex surface of such strip where thus flexed.

12. The apparatus of claim 11 wherein said brush means is a power driven cylindrical rotary brush having its axis of rotation disposed parallel to such diagonal flexure.

13. In apparatus for treating elongated articles such as metal strip and the like, means for longitudinally advancing such strip, means operative to flex such advancing strip diagonally of its longitudinal center line, and brush means operative to power brush the concave surface of V such strip where thus flexed.

14. The apparatus of claim 13 wherein said brush means is a power driven cylindrical rotary brush having its axis of rotation disposed parallel to such diagonal flexure.

15. The method of treating continuous elongated work such as metal strip and the like which comprises continuously longitudinally advancing such strip, transverse- 12 1y flexing such advancing strip diagonally of its longitudinal center line, and simultaneously power brushing both the convex and concave surfaces of such strip where thus flexed in directions at right angles to the axis of flexing.

16. The method of treating continuous elongated work such as metal strip and the like which comprises continuously longitudinally advancing such strip, transversely flexing such advancing strip diagonally of its longitudinal center line, and power brushing the convex surface of such strip where thus flexed in a direction at right angles to the axis of flexing.

17. The method of treating continuous elongated work such as metal strip and the like which comprises continuously longitudinally advancing such strip, transverseflexing such advancing strip diagonally of its longitudinal center line, and power brushing the concave surface of such strip where thus flexed in a direction at right angles to the axis of flexing.

18. The method of treating continuous elongated work such as metal ship and the like which comprises continuously longitudinally advancing such strip, transversely flexing such advancing strip first in one direction and then in the opposite direction, and successively power brushing the same surface of such strip where thus convexly flexed and concavely flexed.

19. The method of treating continuous elongated work such as metal strip and the like which comprises continuously longitudinally advancing such strip, transversely flexing such advancing strip diagonally of its longitudinal center line first in one direction and then in the opposite direction, and successively power brushing the same surface of such strip where thus convexly flexed and concavely flexed in direction at right angles to the axis of flexing.

20. In the processing of continuous elongated work such as metal strip and the like, continuously longitudinally advancing such strip, directing such strip in a zigzag path by passing the same about rotary brushes, and tensioning such strip to support the same entirely upon such brushes where thus engaging the latter, wherein such brushes are also driven to power brush the opposed concavely flexed surfaces of such strip and the corresponding convexly flexed surfaces are simultaneously power brushed.

21. The method of surface beneficiating an elongated metal article which comprises longitudinally advancing the same, progressively locally transversely flexing such advancing article at at least four successive stations to provide at least two concave regions and at least two convex regions of each side of such article, such flexing being diagonal of the longitudinal center line of such article and at a different angle at each such station, power brushing such concave and convex regions with rotary brushes arranged with their axes parallel to the corresponding axes of flexing, periodically interrupting effective brushing action while briefly reversing the direction of travel of such article, and then again resuming advance of such article in the original direction while resuming effective brushing action but with such brushes now driven in directions opposite to that in which they were originally rotating, thereby achieving a plurality of brushing actionson any specified surface area in a plurality of different angularly related directions, the brushes engaging such convex regions making a relatively narrow line of contact therewith and the brushes engaging such concave regions making contact therewith over a relatively large area of such article and over relatively large proportions of the brush peripheries.

22. In a method of surface beneficiating an elongated metal article such as strip and the like wherein such article is longitudinally advanced while being subjected to high speed power brushing by a rotary brush in engagement therewith, the steps of periodically reversing the direction of travel of such article while substantially simultaneously ceasing effective brushing thereof, revers- 13 ing the direction of rotation of such brush, and resuming effective brushing of such article thereby While substantially simultaneously resuming advance of such article in the original d rection.

23. The method of surface beneficiating an elongated metal article such as hot rolled steel strip and the like which comprises successively power brushing the same surface of such strip in a plurality of difierent directions diagonally related to the longitudinal center line of such strip, and flexing such strip to present such surface in convex form to the brush at one station and flexing such strip to present such surface in concave form to the brush at another station where performing such brushing operations.

24. Apparatus for power brushing a length of metal strip or the like comprising a succession of pairs of generally opposed parallel cylindrical rotary brushes, said pairs of brushes being offset relative to adjacent pairs to flex such strip passing therebetween in a zigzag path, means operative longitudinally to advance and tension such strip, those of said brushes of each said pair opposed to said brushes over which such strip is thus flexed being positioned to engage the strip surface in a flat region closely adjacent the respective convex region of such strip surface, and power means operative to drive said brushes to brush both such flat regions and the concave regions engaged by said brushes over which said strip is flexed.

25. The apparatus of claim 24 wherein said brushes are disposed diagonally of the longitudinal center line of such strip.

26. The apparatus of claim 24 wherein said pairs of brushes are disposed diagonally of the longitudinal center line of such strip, alternate pairs being relatively angled successively to brush the same portion of such strip in substantially different directions.

27. The apparatus of claim 24 wherein the axes of said brushes are generally horizontal and disposed diagonally of the longitudinal center line of such strip, said axes being slightly tilted from the horizontal sufficiently to compensate for such diagonal arrangement to produce a straight pass as viewed in top plan.

28. The method of treating continuous elongated work such as metal strip and the like which comprises continuously longitudinally advancing and tensioning such stn'p, transversely flexing such advancing strip over a transverse support to produce a convexly curved surface region, and power brushing a flat region of the same surface of such strip closely adjacent such convexly curved surface region where such strip is substantially supported by such transverse support and flattened by such tension adjacent such flexed region, wherein such transverse support is disposed thus to flex such strip diagonally of its longitudinal center line.

References Cited in the file of this patent UNITED STATES PATENTS 197,265 Graham Nov. 20, 1877 225,796 Camp Mar. 23, 1880 1,288,064 Lewis Dec. 17, 1918 2,218,913 Hughes Oct. 22, 1940 2,221,348 Hershey et al. Nov. 12, 1940 2,279,608 Wood Apr. 14, 1942 2,297,976 Nachtman Oct. 6, 1942 2,543,657 Brown Feb. 27, 1951 2,680,938 Peterson June 15, 1954 2,709,142 Durst May 24, 1955 2,757,486 Peterson Aug. 7, 1956 2,759,301 Valette et a1. Aug. 21, 1956 2,784,432 Whaley Mar. 12, 1957 FOREIGN PATENTS 736,217 Great Britain Sept. 5, 1955 

15. THE METHOD OF TREATING CONTINUOUS ELONGATED WORK SUCH AS METAL STRIP AND THE LIKE WHICH COMPRISES CONTINUOUSLY LONGITUDINALLY ADVANCING SUCH STRIP, TRANSVERSELY FLEXING SUCH ADVANCING STRIP DIAPONALLY OF ITS LONGITUDINAL CENTER LINE, AND SIMULTANEOUSLY POWER BRUSHING BOTH THE CONVEX AND CONCAVE SURFACES OF SUCH STRIP WHERE THUS FLEXED IN DIRECTIONS AT RIGHT ANGLES TO THE AXIS OF FLEXING. 